Residential and commercial establishments bag their refuse and this bagged refuse is normally collected by packer trucks at regular intervals. Recycling programs have brought into use blue boxes, carts, etc. and historically municipalities have provided the blue boxes and carts. The pick-up in many municipalities of recyclable waste is a separate pick-up service.
The use of bags for collecting recyclables has many advantages one being it removes the cost from the municipality because bags are generally purchased by the user. Also bags have other benefits as pick-up is cheaper, less time consuming and simpler. Paper waste is also protected by the bags. From a collection point of view drivers can simply throw the bagged waste into the truck and move on to the next location where bags are located. Containers (blue boxes) and carts on the other hand have to be taken to the truck, emptied, and then returned to the curb.
Studies have indicated that recovery rates of recyclable material improves when bags are used in place of blue boxes and containers. From a community point of view bagged waste is tidier because it avoids having loose pages of paper and newspapers blown about the neighbourhood as often occurs when using blue boxes and containers.
Bags can be made of plastics material or paper. The recyclable materials generally consist of various metals such as aluminum and steel cans, plastic containers, and glass bottles or jar as well as fibre material such as newspapers, box board and corrugated paper. The organic waste collected typically includes kitchen organic waste and/or leaf and yard waste. Municipal solid waste includes garbage or material generally destined for landfill. The above materials and combinations thereof are referred to as refuse for the purpose of this description.
Bagged refuse is taken to a handling facility and at that facility it is necessary to have a mechanical bag opener that not only opens the bag but also empties the bag. It is desirable to have the open bag remain as a unitary piece so that it can be readily separated from the contents of the bag. This type of waste handling also has a safety feature in that the contents of the bag are displayed before being handled manually. Often there are hazardous items such as syringes and broken glass in the waste material and these are visible instead of being hidden inside the bag.
A desired characteristic of a mechanical bag opener is that it must handle a wide range of material some of which may be loose and the majority of which will be in the bags. It must handle bags that have been compacted by the packer pick-up trucks and a bag opener must also remove the contents from the bag without shredding the bag into many pieces. The bag opening machine should be able to accept common items found in the waste stream without damaging the machine some of the items for example may be lawn chairs, bicycles, frying pans, children'ss large toys, etc.
Mechanised bag openers are known and by way of example reference may be had to the following U.S. Pat. No.: 5,639,202 issued Jun. 17, 1997 to F. Roycraft; U.S. Pat. No. 5,567,106 issued Oct. 22, 1996 to B. Gassner; U.S. Pat. No. 5,551,825 issued Sep. 3, 1996 to J. Montgomery; U.S. Pat. No. 5,484,247 issued Jan. 16, 1996 to B. Clark, et al; U.S. Pat. No. 5,484,238 issued Jan. 16, 1996 to J. Bielagus; U.S. Pat. No. 5,433,577 issued Jul. 18, 1995 to F. Roycraft; U.S. Pat. No. 5,415,515 issued May 16, 1995 to Bielagus et al; U.S. Pat. No. 5,368,431 issued Nov. 29, 1994 to E. Willey; Canadian Patent documents 2,167,997 published Aug. 3, 1996, Campbell; et al; 2,167,772 published Aug. 2, 1996, Nadarajah and Canadian Patent 2,010,489 issued Jan. 10, 1995 and issued to First Brands Industries Corporation.
Of the foregoing references U.S. Pat. Nos. 5,484,247 and 5,368,431 are considered the most closely related to applicant's apparatus. The bag breaker disclosed in the '247 patent has an in-feed hopper located directly above the bite portion of two counter rotating shafts that are of heavy construction. Because of the feed being vertically downward and directly into the bite, jamming can readily occur and/or brute force power will be required to force the bagged material between the counter rotating rollers. There is no means of controlling the rate of feed to the power driven counter rotating shafts. Also since brute force is used there can occur considerable damage and breakage making later segregating and sorting difficult particularly when glass is contained in the bagged refuse. Another disadvantage of this apparatus is that when winding occurs of the bagged contents on the shaft, as it will, the material will be difficult to remove because it will be wound upon the shafts with a very high torque. A still further disadvantage is the difficulty of accepting or passing large foreign objects between the counter rotating rolls.
The apparatus disclosed in the '431 patent includes an expensive and complicated bag opening apparatus. The bagged refuse is fed by way of a first feed conveyor onto a second input conveyor which discharges into the bite of counter rotating bag slicer and a first paddle wheel assembly. At this station the bags are sliced transverse to the direction of travel of the bagged material. From there the sliced bag and contents thereof are fed to a second pair of counter rotating rollers, the bottom one of which slices the bags longitudinally and the upper one is a second paddle which propels the contents. The transverse and longitudinal slicing obviously will cut the bag into many pieces making later sorting difficult. From the second slicing station the open bags, and contents removed therefrom, move to a further handling station by a discharge conveyor. The first and second paddle wheel assemblies are mounted on arms that pivot and use rigid paddle blades.